# Code walkthrough · GOAT chat agent for native Chromia transactions · Learn Chromia > You can point the project at testnet or mainnet. The CHROMIA_CONFIG object supplies predefined constants for whichever network you pick: Source: https://chromia.com/learn/chromia-goat-chat-agent/codebase-overview/ GOAT chat agent for native Chromia transactionsLesson 4 of 4 1. [01An AI chat agent that sends Chromia transactions](https://chromia.com/learn/chromia-goat-chat-agent/introduction/) 2. [02Set up your project](https://chromia.com/learn/chromia-goat-chat-agent/setup/) 3. [03Explore the chat agent](https://chromia.com/learn/chromia-goat-chat-agent/explore-agent/) 4. [04Code walkthrough](https://chromia.com/learn/chromia-goat-chat-agent/codebase-overview/) [Learn](https://chromia.com/learn/)[GOAT chat agent for native Chromia transactions](https://chromia.com/learn/chromia-goat-chat-agent/) 04 / 04Advanced # Code walkthrough The project consists of two main files: 1. **`index.ts`: Entry point** * Handles environment configuration, blockchain connections, tool setup, and interaction with the user. * Shows how to run blockchain operations securely, with MetaMask signing transactions and the GOAT SDK handling blockchain management. 2. **`tools.ts`: Helper functions** * Holds reusable tools, such as fetching the live CHR price and configuring how the assistant behaves. ## Key components ### 1. **Environment and network setup** You can point the project at **testnet** or **mainnet**. The `CHROMIA_CONFIG` object supplies predefined constants for whichever network you pick: typescript ``` const chromiaNetwork = "testnet"; // Switch to "mainnet" for mainnet operations console.log(chalk.green("✔ Using Chromia network:"), chromiaNetwork); const config = CHROMIA_CONFIG[chromiaNetwork]; ``` **Key points:** * **Predefined configurations:** `CHROMIA_CONFIG` includes ready-made constants for both testnet and mainnet: + `NODE_URL_POOL`: The node URLs used to communicate with the blockchain. + `ECONOMY_CHAIN_BRID`: The identifier of the Economy Chain. + `CHR_ASSET_ID`: The identifier of the CHR token. * **Dynamic targeting:** Pass `"testnet"` or `"mainnet"` to load the matching values from `CHROMIA_CONFIG`. * **Customization:** `CHROMIA_CONFIG` is only a convenience. For advanced cases, skip it and provide your own values. ### 2. **Connect to Chromia and enable transactions** Next, the project opens a connection to the Chromia blockchain and sets up transactions. You can adjust this setup to work with other chains and tokens. typescript ``` const chromiaClient = await createClient({ nodeUrlPool: config.NODE_URL_POOL, blockchainRid: config.ECONOMY_CHAIN_BRID, // Specifies the target chain }); const connection = createConnection(chromiaClient); const evmKeyStore = await createWeb3ProviderEvmKeyStore(window.ethereum); const keystoreInteractor = createKeyStoreInteractor(chromiaClient, evmKeyStore); const baseTools = await getOnChainTools({ wallet: chromia({ client: chromiaClient, accountAddress, keystoreInteractor, assetId: config.CHR_ASSET_ID, // Specifies the token for transfer connection, }), plugins: [sendCHR()], // Adds token transfer functionality }); ``` **Key points:** * **Network targeting:** `NODE_URL_POOL` determines which network you connect to. For a current list of testnet nodes, see the [Chromia Explorer](https://explorer.chromia.com/testnet/cluster/system). * **Custom configuration:** + **Chains:** To connect to a particular chain or dapp, swap out `blockchainRid`. You can look up a chain’s `brid` in the [Chromia Explorer](https://explorer.chromia.com/testnet). + **Tokens:** To use a different token, set `assetId` to that token’s unique identifier. For instance, the `assetId` of tCHR on the Economy Chain is listed under 'Assets' in the [Economy Chain Explorer](https://explorer.chromia.com/testnet/090BCD47149FBB66F02489372E88A454E7A5645ADDE82125D40DF1EF0C76F874). * **MetaMask integration:** MetaMask takes care of signing transactions securely, and the Chromia tools handle communication with the blockchain. ### 3. **Extend tools for real-time price fetching** The `getLiveTokenPrice` helper retrieves live price data from CoinGecko. `index.ts` then wraps it so the assistant can call it. * **Helper function in `tools.ts`:** typescript ``` export const getLiveTokenPrice = async () => { const response = await fetch("https://api.coingecko.com/api/v3/simple/price?vs_currencies=usd&ids=chromaway&include_market_cap=true&include_24hr_vol=true&include_24hr_change=true"); return await response.json(); }; ``` * **Integration in `index.ts`:** typescript ``` const enhancedTools = { ...baseTools, getLiveTokenPrice: { name: "getLiveTokenPrice", description: "Fetches the current CHR price in USD.", parameters: z.object({}), execute: async () => formatPriceData(await getLiveTokenPrice()), }, }; ``` **Key points:** * The **helper function** retrieves price data and is written to be reused. * The **extended tool** exposes it to the assistant at runtime so users can ask about prices. ### 4. **Setting up the AI assistant and configuring its behavior** The assistant answers user questions and carries out blockchain actions. You configure it through environment variables and shape its behavior with `MASTER_PROMPT` in `tools.ts`. * **Assistant setup in `index.ts`:** typescript ``` const openai = createOpenAI({ baseURL: import.meta.env.VITE_AI_BASE_URL, apiKey: import.meta.env.VITE_AI_API_KEY, }); ``` * **Behavior configuration in `tools.ts`:** typescript ```nolines export const MASTER_PROMPT = (priceData: string) => `You are CHRA, a helpful assistant for CHR tokens... `; ``` **Key points:** * **Flexibility:** Any AI service compatible with the OpenAI client standard works with the assistant. * **Customization:** Edit `MASTER_PROMPT` to give the assistant the style and tone your project needs. The Chromia GOAT demo combines blockchain functionality and an AI assistant in a single application. Its modular design separates the blockchain tools from the configurable assistant, so you can reuse either part. Use it as a reference when you need secure transaction signing, blockchain asset handling, or a conversational AI interface in your own project. Written for this site from Chromia’s public course. Code samples are the course’s own. [← Previous**Explore the chat agent**](https://chromia.com/learn/chromia-goat-chat-agent/explore-agent/)[Course done →**Start building**](https://chromia.com/developers/#start) On this page * [Key components](#key-components)